1. Field of the Invention
The presently described technology generally relates to electrical control panels. More specifically, the presently described technology relates to capacitive touch electrical control panels for appliances.
2. Description of the Related Art
Capacitive sensors have become increasingly common and accepted for use in human interfaces and for machine control. In the field of home appliances, there can be found capacitive touch controls operable through functioning user interfaces or control panels. Touch controls, touch switches or touch pads are used to replace conventional mechanical or tactile switches. Unlike tactile or mechanical switches, touch pads contain no moving parts to break or wear out. Moreover, touch pads can be mounted or formed on a continuous substrate sheet, such as a touch panel, without the need for openings in the substrate. The use of touch pads in place of mechanical or tactile switches can therefore be advantageous, particularly in environments where contaminants are likely to be present. Touch panels are also easier to clean than typical mechanical switch panels because they can be made without openings in the substrate that would allow penetration of contaminants. As a result, touch panels can offer a unique “high end” type of control panel experience, allowing a user to activate a control panel switch by placing an item such as a stylus or a finger at an area or a key of the control panel.
In appliance control panels, it is becoming desirable to provide a visual display in conjunction with a control panel. Such a display can be in the form of a small digital screen, or a larger digital interface, such as a liquid crystal display (LCD) screen. The display can offer various modes of display in relation to the function of the control panel. For example, in one mode, a control panel display may display functions associated with adjusting the temperature of the appliance, and in another mode, the control panel display may display functions associated with the filter or dispensing characteristics of the appliance, for example. In these embodiments, it may be valuable to provide a control panel offering capacitive touch keys that operate as a single key in one mode, and as a plurality of keys in another mode.
Currently, the state of the art offers methods such as those depicted in FIG. 1. FIG. 1 depicts a “slider” type of a touch receiver pad 50. The slider touch receiver pad has an upper region 10 and a lower region 20 divided by a diagonal line 30. The slider can approximately detect where on the slider key a user is touching by the amount of capacitance associated in each region. For example, where a user touches on the left side of the slider, the user's finger will likely be primarily touching the lower slider region 20, thereby generating a capacitance signal from lower region 20 that is significantly greater than the capacitance detected from upper region 10. Thus, the slider unit approximates the touch to be on the left side of the pad. Where the capacitance signal is detected as 50% for each region, the slider can approximate that the press is in the middle of the pad.
The slider touch pads, however, require complex algorithms for determining a precise touch position. Further, slider touch pads, due to the shape of the receiving areas, may not always work where the touch receptor pads are separated from the control panel interface and the use of an extender is required.
As a result, there exists an ongoing challenge to have systems and methods for providing a control panel offering multi-function keys utilizing or interacting with extenders.